One of Helmut Kohl's sons is married to a Turkish woman. /irony
Of course, Helmut Kohl's sons are not on speaking terms with their father.
Kohl might not have mentioned 50% publicly, but he was publicly talking about the 'mistake' of letting so many immigrants in etc quite constantly in his first years in office.
There is also the associated irony that the policies the Kohl government dared to implement with the goal of keeping legal immigrants' families out had the opposite effect.* That Turkey was a military dictatorship at the time played a role, of course.
*it was pretty common until then for Turkish - and South Italian - men to work here and have their families at home. New restrictions on the age up to which children could follow their parents legally meant that anyone who had schoolchildren at home moved them here, creating a late wave of Turkish and Italian immigration. I went to primary school with some of these kids.